BLUE BELL, Pa., Sept. 6, 2012 /PRNewswire/ -- Inovio Pharmaceuticals, Inc. (NYSE MKT: INO) announced today that the interim analysis of its SynCon® universal H1N1 influenza vaccine showed that it generated protective HAI titers against some of the most prevalent strains of H1N1 influenza from the past 100 years in a phase I clinical trial. Because the SynCon® approach incorporates sequence information from multiple divergent strains, the vaccine is not matched to any of the historical flu strains. The achievement of protective titers against multiple unmatched strains represents a major step towards Inovio's ultimate goal to develop a universal influenza vaccine to protect against known and newly emerging strains of influenza.

"With respect to influenza, our ultimate objective is to develop a universal vaccine capable of providing years of true preemptive protection across subtypes and strains," said Dr. J. Joseph Kim, Inovio's President and CEO. "This is a challenging goal but this proof-of-principle H1N1 data demonstrates the potential of our SynCon® approach to generate cross-protective HAI titers against multiple unmatched influenza strains. These results are an important addition to our previously reported H5N1 phase I data and a validating achievement on our ongoing effort to develop a safe vaccine that provides immunity against the ever-changing influenza virus."

The current open label phase I study evaluated two synthetic H1N1 hemagglutinin (HA) plasmids designed to broadly protect against unmatched influenza strains within different branches of the H1N1 subtype. These plasmids were delivered in healthy adults with Inovio's CELLECTRA® intradermal electroporation device up to three times. The delivered vaccine was well tolerated; reported adverse events and injection site reactions were mild to moderate and required no treatment.

Researchers exposed blood samples from the vaccinated subjects to each of the nine key H1N1 viruses in circulation over the last 100 years: eight were H1N1 strains used to formulate the seasonal vaccines of the last 25 years; one was the H1N1 strain that caused the 1918 Spanish flu, which killed over 40 million people. These unmatched influenza strains were used to assess the generation of hemagglutination inhibition (HAI) titers meeting or exceeding 1:40. An HAI titer of 1:20 is generally regarded as a positive vaccine response, while 1:40 is the level recognized as a protective immune response against influenza in humans. Demonstrating Inovio's synthetic vaccine's broad cross-reactive coverage, a significant percentage of subjects immunized with Inovio's SynCon® vaccine had an HAI titer of 1:40 or higher against each of the nine H1N1 strains tested, ranging from a 30% response rate to the A/Brisbane/59/07 strain to a 100% response rate to the A/Beijing/262/95 strain. The benchmark for the current licensed seasonal flu vaccines, which are based on matching the vaccine HA sequence to that of the circulating strain, is to have greater than 65% of the vaccines generate an HAI titer of 1:40 or higher against the matched vaccine strain.

By design, Inovio's SynCon® universal flu vaccine is not matched to any single virus and was not matched to any of the strains tested in this study. The vaccine recipients generated protective HAI responses against the H1N1 A/South Carolina/1/18 strain from the 1918 Spanish flu as well as all the H1N1 strains which were part of the annual seasonal trivalent inactivated flu vaccines (TIV) since 1986, including: A/Taiwan/1/86, A/Texas/36/91, A/Bayern/07/95, A/Beijing/262/95, A/New Caledonia/20/99, A/Solomon Islands/03/06, A/Brisbane/59/07, A/California/07/09. The HAI titers in the positive responders ranged from 1:40 to greater than 1:1280.

Compared to the seasonal TIV (trivalent influenza vaccine)-immunized control group, which is matched to the current H1N1 seasonal flu strain (A/California/07/09), those immunized with Inovio's vaccine generated a higher or similar percentage of positive HAI titer responders against all of the strains except for A/California/07/09. As anticipated, the TIV recipients generated the best HAI titers against the matched strain, but did not generate vaccine-induced response rates against the unmatched strains.

This phase I study is ongoing, with additional results from a higher dose group expected in 2013. Inovio is also conducting optimization studies in animal models to further strengthen its H1N1 vaccine's potency against all strains, especially the current circulating strain, A/California/07/09, as well as to reduce the number of injections needed to generate protective responses against multiple strains.

Today's announced results and prior achievements provide further evidence of the capability of Inovio's synthetic consensus design approach to create vaccines capable of providing universal protection against changing strains of a pathogen. Inovio's intent is to leverage the greater breadth of immune responses achievable using its SynCon® vaccine design to revolutionize the flu vaccine market. Inovio has a two-pronged development strategy targeting the pandemic and seasonal influenza vaccine market segments. Within this strategy, we have a particular focus on the elderly market segment, which has the greatest unmet need.

First, we are attempting to better guard against future flu pandemic strains. Inovio recently reported that its SynCon® H5N1 plasmid construct generated high levels of antigen-specific binding antibodies and exhibited a four-fold or greater rise in geometric mean titers and HAI titers ranging from 1:20 to 1:80 against six different H5N1 virus strains. A four-fold rise in HAI titers, compared to pre-vaccination, is considered an important indicator of immune activation. Our plan with this product is to access the pandemic stockpiling market, which is dominated by government buyers.

Second, we aim to develop a universal seasonal vaccine to protect us from future H1N1, H3N2, and the Type B influenza strains, the subtypes comprising today's TIV. In addition to the ongoing animal and human studies for H1N1, the Company is completing tests in animal models of its vaccine constructs for A/H3N2 and Type B influenza. Our goal is to develop vaccines that can also generate HAI titers exceeding 1:40 against unmatched strains within the H3N2 and Type B subtypes.

More specifically, our goal is to develop a more effective flu vaccine for those over 65 years of age, who currently account for about 90% of seasonal flu-related deaths. Inovio recently launched a third influenza study, called FLUPRIME, using its H1N1 construct alone and in combination with the 2012 seasonal influenza vaccine (TIV) to evaluate the results of these regimens in this population. We expect immunogenicity data in 2013.

About Inovio Pharmaceuticals, Inc.

Inovio is revolutionizing vaccines to prevent and treat today's cancers and challenging infectious diseases. Its SynCon® vaccines are designed to provide universal cross-strain protection against known as well as newly emergent unmatched strains of pathogens such as influenza. These synthetic vaccines, in combination with Inovio's proprietary electroporation delivery, have been shown in humans to generate best-in-class immune responses with a favorable safety profile. Inovio's clinical programs include phase II studies for cervical dysplasia, leukemia and hepatitis C virus and phase I studies for influenza and HIV. Partners and collaborators include the University of Pennsylvania, Merck, ChronTech, National Cancer Institute, U.S. Military HIV Research Program, NIH, HIV Vaccines Trial Network, University of Southampton, US Dept. of Homeland Security and PATH Malaria Vaccine Initiative. More information is available at www.inovio.com.

This press release contains certain forward-looking statements relating to our business, including our plans to develop electroporation-based drug and gene delivery technologies and DNA vaccines and our capital resources. Actual events or results may differ from the expectations set forth herein as a result of a number of factors, including uncertainties inherent in pre-clinical studies, clinical trials and product development programs (including, but not limited to, the fact that pre-clinical and clinical results referenced in this release may not be indicative of results achievable in other trials or for other indications, that the studies or trials may not be successful or achieve the results desired, that pre-clinical studies and clinical trials may not commence or be completed in the time periods anticipated, that results from one study may not necessarily be reflected or supported by the results of other similar studies and that results from an animal study may not be indicative of results achievable in human studies), the availability of funding to support continuing research and studies in an effort to prove safety and efficacy of electroporation technology as a delivery mechanism or develop viable DNA vaccines, the adequacy of our capital resources, the availability or potential availability of alternative therapies or treatments for the conditions targeted by the company or its collaborators, including alternatives that may be more efficacious or cost-effective than any therapy or treatment that the company and its collaborators hope to develop, evaluation of potential opportunities, issues involving product liability, issues involving patents and whether they or licenses to them will provide the company with meaningful protection from others using the covered technologies, whether such proprietary rights are enforceable or defensible or infringe or allegedly infringe on rights of others or can withstand claims of invalidity and whether the company can finance or devote other significant resources that may be necessary to prosecute, protect or defend them, the level of corporate expenditures, assessments of the company's technology by potential corporate or other partners or collaborators, our ability to secure new partnerships and collaborations, capital market conditions, the impact of government healthcare proposals and other factors set forth in our Annual Report on Form 10-K for the year ended December 31, 2011, our Form 10-Q for the quarter ended June 30, 2012, and other regulatory filings from time to time. There can be no assurance that any product in Inovio's pipeline will be successfully developed or manufactured, that final results of clinical studies will be supportive of regulatory approvals required to market licensed products, or that any of the forward-looking information provided herein will be proven accurate.